Connecting a high voltage power source to a device, such as an electrode, within a vacuum chamber typically involves an insulated feed through which is sealed within a passage through a wall of the chamber. The feed throughs generally combine metal components for strength or conductivity and ceramic components for insulating high voltage conductors from the wall of the chamber. Such feed throughs are useful for a variety of connections, including connections between external power sources and electrical devices within vacuum processing chambers which produce integrated circuits. The feed throughs can be installed in any chamber wall and can seal ambient conditions from high vacuum within the chamber.
The combination of conducting and insulating components in a high voltage feed through typically requires joining of the components to provide a vacuum tight seal and an insulated passage for high voltage conductors. Metal and ceramic components can be joined by brazing with alloys which bond to both the metal components and the ceramic components. The brazed connections provide sufficient vacuum tight seals, however, thermal expansion and contraction of the metal and ceramic components can weaken and break the ceramic components or the brazed connections. Thus, feed throughs which combine metal and ceramic components are typically used in walls which are not heated or cooled substantially during vacuum processing. There remains a need for a high voltage feed through which is resistant to thermal stresses during vacuum processing.